the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
icon

relay diagram for car pc


Post ReplyPost New Topic
< Prev Topic Next Topic >
rsa_sean 
Member - Posts: 4
Member spacespace
Joined: April 26, 2007
Location: United States
Posted: February 25, 2009 at 10:35 AM / IP Logged  
Could someone please validate this diagram, I am by no means an electronics expert but I think this will do what I am looking for:
The scenario:
I have a CarPC that has power supply unit (PSU) designed for car use, the supply has an auto power on ( based on a switched 12v line). I would like to begin the power up process by using my keyfob and the neg trigger from the dome lights to power the PSU's switched line, then when I turn the ignition the switched line would then power the PSU's switched line.
Does this look like a viable solution ??
relay diagram for car pc -- posted image.
Other notes:
The dome lights turn on for a few minutes then power off. this is not an issue because the PSU I have has a shutdown controller.
Also the dome light turn off when the key is turned.
Thanks in advance.
KPierson 
Platinum - Posts: 3,527
Platinum spaceThis member consistently provides reliable informationspace
Joined: April 14, 2005
Location: Ohio, United States
Posted: February 25, 2009 at 11:28 AM / IP Logged  

I would put a diode across each coil.  You could probably get away without one on the right relay, but the left relay will need one to protect the transistorized outout of the BCM that wasn't designed to handle inductive loads.

Other then that it looks good and I would think it would work.

Kevin Pierson
rsa_sean 
Member - Posts: 4
Member spacespace
Joined: April 26, 2007
Location: United States
Posted: February 25, 2009 at 12:35 PM / IP Logged  
So you would recommend it like this ?
relay diagram for car pc -- posted image.
rsa_sean 
Member - Posts: 4
Member spacespace
Joined: April 26, 2007
Location: United States
Posted: February 25, 2009 at 12:37 PM / IP Logged  
how many amps should the diodes be able to handle ?
would a 1 amp be sufficient or should I get something larger 6A ???
KPierson 
Platinum - Posts: 3,527
Platinum spaceThis member consistently provides reliable informationspace
Joined: April 14, 2005
Location: Ohio, United States
Posted: February 25, 2009 at 3:45 PM / IP Logged  
a 1A diode would be fine.
Kevin Pierson
rsa_sean 
Member - Posts: 4
Member spacespace
Joined: April 26, 2007
Location: United States
Posted: February 26, 2009 at 7:39 PM / IP Logged  
Could the diode just be placed on the negative trigger???
How would I place a diode across the coil ?? does anyone have a picture that shows what this physically looks like ?
KPierson 
Platinum - Posts: 3,527
Platinum spaceThis member consistently provides reliable informationspace
Joined: April 14, 2005
Location: Ohio, United States
Posted: February 26, 2009 at 8:17 PM / IP Logged  
No, it has to go across the coil.  You wire the striped side to the (+) side of the coil and the non striped side to the (-) side of the coil.
Kevin Pierson

Sorry, you can NOT post a reply.
This topic is closed.

  Printable version Printable version Post ReplyPost New Topic
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot delete your posts in this forum
You cannot edit your posts in this forum
You cannot create polls in this forum
You cannot vote in polls in this forum

  •  
Search the12volt.com
Follow the12volt.com Follow the12volt.com on Facebook
Monday, July 7, 2025 • Copyright © 1999-2025 the12volt.com, All Rights Reserved Privacy Policy & Use of Cookies
Disclaimer: *All information on this site ( the12volt.com ) is provided "as is" without any warranty of any kind, either expressed or implied, including but not limited to fitness for a particular use. Any user assumes the entire risk as to the accuracy and use of this information. Please verify all wire colors and diagrams before applying any information.

Secured by Sectigo
the12volt.com spacer
the12volt.com spacer
the12volt.com spacer
Support the12volt.com
Top
the12volt.com spacer
the12volt.com spacer